Ran through a bunch of benches and games with these as a fresh install on a fresh OS and had no issues in any game.

CrossFire 6950's flashed to 6970's at 950 core 1450 mem all at 2560 x 1600.

Had issues in Fallout 3 with 10.12 and now I don't, not sure if it was an OS thing or a driver thing though since both are new.